1. Field of the Invention
The present invention relates to a light source apparatus for endoscope configured to cool a plurality of heat-generating portions.
2. Description of the Related Art
Hitherto, endoscopes each configured to include an insertion portion having a shape of an elongated tube have been widely used in a medical field or an industrial field, for example. Among the endoscopes, a medical endoscope used in the medical field is configured to be able to observe an organ and the like by inserting the insertion portion in a subject such as a body cavity of a living body, or perform various types of treatment on the organ and the like with use of a treatment instrument inserted in a treatment instrument insertion channel included in the endoscope, as necessary. In addition, an industrial endoscope used in the industrial field is configured to be able to observe or inspect states of flaws or corrosion in an object, for example, apparatuses or machinery such as a jet engine or plant piping by inserting the insertion portion in the object.
In many cases, a target that is observed, for example, with use of the types of endoscopes as above is in a dark place such as a body cavity or the inside of an apparatus, and hence a light source apparatus configured to irradiate the target with illumination light is used. Solid-state light-emitting elements such as an LED (light emitting diode) or a laser light source are used in some light source apparatuses (hereinafter referred to as “light source apparatuses for endoscope”) used in endoscopes in recent years. A plurality of solid-state light-emitting elements are provided in the types of light source apparatuses for endoscope as above so that illumination light having a desired color such as white light can be emitted.
In the light source apparatuses for endoscope as above, the calorific value of the respective solid-state light-emitting elements tends to increase because a large amount of illumination light needs to be emitted. Thus, in a conventional light source apparatus for endoscope, a cooling apparatus for cooling each solid-state light-emitting element serving as a heat source is included in a housing. The cooling apparatus in the conventional light source apparatus for endoscope is typically configured by components such as a cooling fan, a heat sink, and a heat pipe. The types of light source apparatuses for endoscope as above are proposed in International Publication No. WO2015/178054A1, International Publication No. WO2015/064470A1, and Japanese Patent Application Laid-Open Publication No. 2012-14992, for example, in various forms.
In the light source apparatuses for endoscope disclosed in International Publication No. WO2015/178054A1, International Publication No. WO2015/064470A1, Japanese Patent Application Laid-Open Publication No. 2012-14992, and the like, a flow path for cooling in a housing is divided into a plurality of flow paths.
On the other hand, in recent years, a light source apparatus for endoscope in which a larger number of solid-state light-emitting elements serving as light-emitting portions and heat sources are arranged has been proposed. Further, an apparatus including an even larger number of solid-state light-emitting elements is expected to be proposed in the future. When the number of the arranged solid-state light-emitting elements serving as light-emitting portions and heat sources increases as above, the calorific value increases by the increased solid-state light-emitting elements. In the case as above, it is obvious that a higher cooling efficiency is demanded for the cooling apparatus applied in the light source apparatus for endoscope.